Simulation of 24-pulse autotransformer based AC—DC converter employing pulse multiplication with direct torque controlled induction motor drive load

In this paper a 24 pulse autotransformer based ac-dc converter has been proposed to improvement power quality at the point of common coupling (PCC). The idea is to use an autotransformer based 12-pulse ac-dc converter using a DC ripple reinjection technique to double its pulse numbers (providing a 24-pulse AC-DC converter). A polygon connected autotransformer is used to produce 12-pulses with flexibility to adjust its voltage ratio for producing DC-link voltage as that of a 6-pulse diode bridge rectifier. The proposed 24-pulse AC-DC converter is utilized to improve the power quality indices at AC mains feeding a direct torque controlled induction motor drive (DTCIMD) load. Simulation results confirmed that the proposed topology has been able to eliminate harmonic currents up to 21^st order at the AC mains under different loading conditions. Furthermore, a set of power quality indices at the input AC mains are compared between the simulation results using the proposed topology and the conventional 6-pulse and 12 pulse converters under different loading conditions.